Huawei HG659 wireless 5 GHz problems

Devices connected to the modem via WLAN 5 GHz stop connecting to the internet regularly. I can change to WLAN 2.4 GHz: and performance is normal, but not an ideal solution in an appartment block with crowded 2.4 GHz. It seems that there is a newer firmware version than the current version 100R001C216B011. I appreciate an update in the hope that it will fix the WLAN 5 GHz connection problems. Thanks.